Process for preparing fine zeolite particles

ABSTRACT

A process for efficiently preparing fine zeolite particles comprising synthesizing zeolite in the presence of an alkaline earth metal-containing compound and/or with controlling the preparation process of zeolite, thereby giving fine zeolite particles being composed of crystalline aluminosilicate, the fine zeolite particles having a fine average primary particle size, being excellent in the cationic exchange properties and the oil-absorbing ability, having a fine average aggregate particle size, and being excellent in the dispersibility; fine zeolite particles obtainable by the above process; and a detergent composition comprising the fine zeolite particles, the detergent composition being excellent in the detergency.

TECHNICAL FIELD

The present invention relates to a process for preparing fine zeoliteparticles, fine zeolite particles obtainable by the process, and adetergent composition comprising the fine zeolite particles.

BACKGROUND ART

Zeolite has been utilized for detergent builders as a water-softeningagent owing to its ion-exchange properties. The ion exchange propertiesare greatly dependent on the primary particle size of the zeolite. Sincezeolite having a very fine primary particle size is excellent in theionic exchange speed, it has been known to exhibit a high detergingperformance.

In addition, there have been known that the fine zeolite particles havethe merits of having little deposition on clothes and reducingturbidity, so that the fine zeolite particles are useful as detergentbuilders.

As a process for preparing such fine zeolite particles, there are givenexamples in which synthesis is completed under specified feedingcomposition of the raw materials and reaction conditions (temperatureand time), when zeolite is synthesized by mixing sodium aluminate withsodium silicate as disclosed in Japanese Patent Laid-Open Nos. Sho60-127218 and Sho 62-275016. When very fine zeolite is synthesized bythe process as described above, the process has to be carried out undercertain restricted conditions in the feeding composition of the rawmaterials and the reaction conditions, so that there arise problems suchas lowered productivity.

There has been reported that the particle size of zeolite is made veryfine by adding a soluble hydrocarbon such as saccharose as disclosed inJapanese Patent Laid-Open No. Sho 60-118625. However, when the presentinventors have applied this process to the synthesis of zeolite, aneffect of reducing a primary particle size could not be found even whenadding the soluble hydrocarbon as described above.

On the other hand, the alkaline earth metal is an element which can beeasily substituted with Na in zeolite. Therefore, from the viewpoint ofthe function as an ion-exchangeable cation, there are many cases wherethe alkaline earth metal is considered to have the same value as thealkali metal. Japanese Patent Laid-Open No. Sho 55-116617 discloses thatzeolite is utilized as an adsorbent having heat stability, whereinsodium in zeolite is partly substituted with an alkaline earth metal.

However, there have not yet been any reports describing that an alkalineearth metal is intentionally and positively added during synthesis ofzeolite, to give a product which exhibits an excellent function as awater-softening agent, nor any reports describing that the alkalineearth element is an essential element indispensable for making itsprimary particle size small.

In addition, there has been tried to make the particle size small fromthe viewpoint of preparation process. For instance, Japanese PatentLaid-Open No. Sho 62-46494 discloses that zeolite is mechanicallypulverized by utilizing various kinds of mixing apparatus. However,there is much room for improvement from the viewpoints of theperformance of the fine zeolite particles and the production efficiency.

An object of the present invention is to provide a process forefficiently preparing fine zeolite particles comprising synthesizingzeolite in the presence of an alkaline earth metal-containing compoundand/or with controlling the preparation process of zeolite, therebygiving fine zeolite particles being composed of crystallinealuminosilicate, the fine zeolite particles having a fine averageprimary particle size, being excellent in the cationic exchangeproperties and the oil-absorbing ability, having a fine averageaggregate particle size, and being excellent in the dispersibility; finezeolite particles obtainable by the above process; and a detergentcomposition comprising the fine zeolite particles, the detergentcomposition being excellent in the detergency.

The above object and other objects of the present invention will beapparent from the following description.

DISCLOSURE OF INVENTION

Specifically, the present invention relates to:

-   -   [1] a process for preparing fine zeolite particles comprising        reacting a silica source with an aluminum source in the presence        of an alkaline earth metal-containing compound;    -   [2] a process for preparing fine zeolite particles comprising        feeding for reaction an aluminum source and/or a silica source        into a circulating line connected to a reaction tank;    -   [3] the process according to item [1] above, wherein the        aluminum source and/or the silica source are fed for reaction        into the circulating line connected to the reaction tank;    -   [4] fine zeolite particles obtainable by the process according        to the process of any one of items [1] to [3] above; and    -   [5] a detergent composition comprising the fine zeolite        particles of item [4] above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing one embodiment of an apparatus forpreparing fine zeolite particles according to the present invention;

FIG. 2 is a schematic view showing another embodiment of an apparatusfor preparing fine zeolite particles according to the present invention;

FIG. 3 is a schematic view showing still another embodiment of anapparatus for preparing fine zeolite particles according to the presentinvention;

FIG. 4 is a schematic view showing still another embodiment of anapparatus for preparing fine zeolite particles according to the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

In the process for preparing fine zeolite particles of the presentinvention, there are mainly two embodiments. Specifically, the featureof the first embodiment resides in that a silica source is reacted withan aluminum source in the presence of an alkaline earth metal-containingcompound. On the other hand, the feature of the second embodimentresides in that an aluminum source and/or a silica source is fed forreaction into a circulating line connected to a reaction tank. In theprocess for preparing fine zeolite particles of the present invention,the restrictions in the feeding composition for raw materials, reactionconditions, and like can be reduced, whereby the desired fine zeoliteparticles of the present invention can be efficiently obtained accordingto this process.

In the present specification, the term “cationic exchange properties”refers to both cationic exchange speed and cationic exchange capacitywhich are described in detail below. The term “aqueous liquid” refers toa liquid containing a given ingredient in water as a medium, and theliquid can take any form such as an aqueous solution, a suspension, adispersion, or the like. The term “line-mixing” refers to a process inwhich a plural ingredients (raw materials and the like) aresubstantially homogeneously mixed in a line such as a feed linedescribed below. The first embodiment and the second embodiment will besequentially explained hereinbelow.

First, the first embodiment will be explained. Usable silica source andaluminum source are not particularly limited. It is preferable to usethe silica source and the aluminum source in the form of an aqueousliquid, from the viewpoints of homogeneity of the reaction anddispersibility. The silica source includes, for instance, commerciallyavailable water glass. A silica source with adjusted molar ratios andconcentrations can be prepared by adding water or an alkali hydroxide tothe water glass as desired.

In addition, the aluminum source is not particularly limited. Thealuminum source includes aluminum hydroxide, aluminum sulfate, aluminumchloride, alkali metal aluminates such as potassium aluminate and sodiumaluminate, and the like. Among them, sodium aluminate is especiallypreferably used, from the viewpoint of high reactivity. These compoundscan be used as the aluminum source by adjusting to appropriate molarratio and concentration by using an alkali hydroxide and water asoccasion demands. For instance, an aluminum source can be prepared bymixing aluminum hydroxide and sodium hydroxide in water, thereafterheating and dissolving the mixture, to give a sodium aluminate solution,and adding the resulting solution to water with stirring to make anaqueous liquid. In addition, the adjustment of the molar ratio and theconcentration as described above can be also carried out by previouslysupplying water to a reaction tank, and adding thereto an aqueous alkalimetal aluminate at a high concentration and an alkali hydroxide.

In the alkaline earth metal-containing compound which is coexistent inthe reaction system, the alkaline earth metal includes Mg, Ca, Sr, Ba,and the like, among which Mg and Ca can be suitably used, from theviewpoints of convenience in the availability of the raw materials andcosts. These compounds may be used alone or in admixture of two or morekinds. These compounds are added to the reaction system as hydroxides ofthe alkaline earth metals or alkaline earth metal salts of carbonates,sulfates, chlorides, nitrates, and the like. In addition, it ispreferable that the alkaline earth metal-containing compound is added inthe form of an aqueous liquid, from the viewpoint of homogeneity of thereaction and the like. It is particularly preferable to use the compoundin the form of a water-soluble salt, and especially, aqueous chloridesof Ca, Mg and the like are favorably used. The hydroxide of an alkalineearth metal or the alkaline earth metal salt should be at leastcoexistent during the reaction of the silica source with the aluminumsource. It is especially preferable to previously add the alkaline earthmetal-containing compound in an aqueous liquid state to the silicasource and/or the aluminum source. It is even more preferable topreviously add the alkaline earth metal-containing compound to thesilica source, from the viewpoint of making the average primary particlesize very fine. In this case, it is preferable to previously add anentire alkaline earth metal-containing compound, but it may beacceptable to only add a part thereof. Also, thereafter, it ispreferable that these silica source and aluminum source are mixed tocarry out synthesis reaction of zeolite.

In the first embodiment of the present invention, contrary to theprocess of substituting Na ions with alkaline earth metal ions after thesynthesis of zeolite, the alkaline earth metal is incorporated into thezeolite structure during the synthesis, so that the alkaline earth metalacts on a network of the zeolite, thereby forming zeolite having a veryfine average primary particle size. From these viewpoints, it ispreferable that the alkaline earth metal is previously made to becoexistent with the silica source having a high affinity therewith. Inaddition, it is desired that the alkaline earth metal partakes in thereaction at the initial stage of the reaction and/or during thecrystallization. In the case of addition of the alkaline earth metalafter the crystallization is once terminated, there cannot be obtainedfine zeolite particles as excellent as those obtained in the firstembodiment of the present invention.

The alkali metal-containing compound such as an alkali hydroxidementioned above can be used as desired for the adjustment of the molarratio or the concentration of the silica source and/or the aluminumsource. Besides the above, the compound may be separately used. Whenseparately used, such a compound can be used in the same manner as thealkali metal-containing compound. Preferable alkali metals are Na and/orK.

In this embodiment, the phrase “previously add” refers to a process, forinstance, where an alkaline earth metal-containing compound ispreviously substantially homogeneously mixed with a silica source and/oran aluminum source before the reaction of the silica source with thealuminum source.

When the alkali metal and/or the alkaline earth metal is contained inthe silica source and/or the aluminum source, the alkalimetal-containing compound and/or the alkaline earth metal-containingcompound, which is preferably in the form of an aqueous liquid, is addedto the silica source and/or the aluminum source or vice versa.

The feeding composition in the first embodiment of the present inventionis such that an SiO₂/Al₂O₃ molar ratio is preferably 0.5 or more, morepreferably 1.5 or more, from the viewpoint of stability of the crystalstructure, and that the SiO₂/Al₂O₃ molar ratio is preferably 6 or less,more preferably 4 or less, especially preferably 2.5 or less, from theviewpoint of cationic exchange properties.

In addition, as to the feeding composition of the alkaline earthmetal-containing compound, the alkaline earth metal (Me) is expressed inthe form of an oxide, and the feeding composition is such that anMeO/Al₂O₃ molar ratio is preferably 0.005 to 0.1, wherein the MeO/Al₂O₃molar ratio is preferably 0.005 or more, more preferably 0.01 or more,from the viewpoint of an effect of making the average primary particlesize very fine, and wherein the MeO/Al₂O₃ molar ratio is preferably 0.1or less, more preferably 0.08 or less, still more preferably 0.05 orless, especially preferably 0.03 or less, from the viewpoint of cationicexchange properties.

As to the feeding composition of the alkali metal-containing compound,the alkali metal (M) is expressed in the form of an oxide, and thefeeding composition is such that an M₂O/Al₂O₃ molar ratio is preferably0.2 to 8, wherein the M₂O/Al₂O₃ molar ratio is preferably 0.2 or more,more preferably 1.5 or more, from the viewpoint of rate ofcrystallization, and wherein the M₂O/Al₂O₃ molar ratio is preferably 8or less, more preferably 4 or less, from the viewpoint of yield. Inaddition, as the feeding composition of the alkali metal-containingcompound and water in the reaction system, an M₂O/H₂O molar ratio ispreferably 0.03 or more, more preferably 0.04 or more, from theviewpoints of improving rate of crystallization and making the averageprimary particle size very fine. In addition, the M₂O/H₂O molar ratio ispreferably 0.07 or less, more preferably 0.06 or less, from theviewpoint of cationic exchange properties.

The concentration of the solid content during the reaction is preferably10% by weight or more, more preferably 15% by weight or more, from theviewpoint of productivity. Also, the concentration of the solid contentis preferably 50% by weight or less, 40% by weight or less, from theviewpoint of flowability of the slurry. Here, the concentration of thesolid content during the reaction is defined as the concentration of thesolid content based on the entire amount of a water-containing slurry,wherein the concentration of solid content is calculated by assumingthat the weight of elements of Si, M, Al, and Me in the raw materials iscalculated as oxides thereof, the raw materials being added to have themolar ratios given above.

The reaction is preferably carried out according to the processcomprising placing a silica source, an aluminum source, and an aqueousliquid of an alkaline earth metal-containing compound in separatecontainers, respectively (an alkali metal being contained in the silicasource and/or the aluminum source); adding the aqueous liquid of analkaline earth metal-containing compound to the silica source and/or thealuminum source; and thereafter mixing the silica source with thealuminum source. Among them, a process comprising adding an aqueousliquid of an alkaline earth metal-containing compound to a silicasource; thereafter adding the resulting mixture to an aluminum source oradding an aluminum source to the resulting mixture to carry out thereaction is especially preferable. In addition, when such silica sourceand aluminum source are mixed, the period of time required for theiraddition is preferably 1 to 50 minutes, more preferably 1 to 20 minutes,from the viewpoint of making the average aggregate particle size veryfine.

The reaction temperature is preferably 25° to 100° C., more preferably40° to 60° C., especially preferably 50° to 55° C. The reactiontemperature is preferably 25° C. or more, more preferably 40° C. ormore, especially preferably 50° C. or more, from the viewpoint ofreaction rate. In addition, the reaction temperature is preferably 100°C. or less, more preferably 60° C. or less, especially preferably 55° C.or less, from the viewpoints of energy loads and withstanding pressureof a reaction tank.

In addition, the formed slurry becomes viscous by the abruptgel-formation reaction at the initial stage of the reaction. Therefore,it is preferable that the slurry is vigorously stirred in order toaccelerate the reaction of the slurry.

The reaction time is not particularly limited. The reaction time ispreferably 1 to 180 minutes from the termination of the addition of theentire feeding components, more preferably 2 to 60 minutes therefrom,still more preferably 4 to 20 minutes therefrom, from the viewpoints ofproductivity and stability of the reaction.

The crystallization is progressed by aging the mixture after thereaction with stirring. The aging temperature is not particularlylimited. The aging temperature is preferably 50° C. or more, morepreferably 60° C. or more, especially preferably 80° C. or more, fromthe viewpoint of rate of the crystallization. In addition, the agingtemperature is preferably 100° C. or less, from the viewpoints of energyloads and withstanding pressure of the reaction tank. The aging time isnot particularly limited. It is preferable that the aging time isusually 1 to 300 minutes, from the viewpoint of productivity. Duringaging, it is preferable that aging is carried out until the highest peakintensity of the X-ray diffraction patterns reaches the maximum, oruntil the cationic exchange capacity reaches the maximum.

After the termination of aging, the crystallization is terminated byfiltering and washing the slurry, or neutralizing the slurry with anacid. When filtering and washing the slurry, it can preferably becarried out until pH of the filtrate attains to preferably 12 or less.In addition, when neutralizing the slurry with an acid, the acid used isnot particularly limited. The acid includes sulfuric acid, hydrochloricacid, nitric acid, carbon dioxide, oxalic acid, citric acid, tartaricacid, fumaric acid, succinic acid, and the like. Among them, sulfuricacid and carbonic acid gas are preferable, from the viewpoints ofcorrosion resistance of apparatus and costs. It is preferable that pH ofthe slurry is adjusted to 7 to 12. After the termination of thecrystallization, the slurry may be dried as desired, to give the finezeolite particles of the present invention.

Next, the second embodiment for a process for preparing fine zeoliteparticles of the present invention will be explained. Usable silicasource and aluminum source are the same as those in the first embodimentdescribed above. In addition, it is also preferable in this embodimentthat the synthesis reaction of zeolite is carried out in the presence ofthe alkaline earth metal-containing compound. In this case, it ispreferable to previously add the alkaline earth metal-containingcompound, preferably in an aqueous liquid state, to the silica sourceand/or the aluminum source, and it is more preferable to previously addthe alkaline earth metal-containing compound to the silica source. It ispreferable to previously add an entire alkaline earth metal-containingcompound to the silica source and/or the aluminum source, but it may beacceptable to only add a part of the alkaline earth metal-containingcompound thereto. Exemplifications of the alkaline earthmetal-containing compounds and the alkaline earth metals containedthereof, and embodiments using such compounds are the same as those inthe first embodiment described above.

In this embodiment, the phrase “previously add” refers to an embodimentof a process where an alkaline earth metal-containing compound ispreviously substantially homogeneously mixed with a silica source and/oran aluminum source before feeding the silica source and the aluminumsource. An example thereof includes, for instance, an embodiment of aprocess where an alkaline earth metal-containing compound is directlyadded to a silica source and/or an aluminum source and mixed therewith,and thereafter the silica source is mixed with the aluminum source tocarry out the reaction. The phrase also refers to another embodiment ofa process where it is not necessary that an alkaline earthmetal-containing compound is directly added to and mixed with a silicasource and/or an aluminum source, but the alkaline earthmetal-containing compound is mixed part of the way of feeding the silicasource and/or the aluminum source. An example thereof includes, forinstance, an embodiment of a process comprising carrying out line-mixingwherein a feed line for a silica source and/or an aluminum source islinked with a feed line for an alkaline earth metal-containing compoundat a position immediately before a circulating line for line-mixing.Alternatively, a process may comprise directly supplying an alkalineearth metal-containing compound to a reaction tank. It is desired thatan alkaline earth metal-containing compound partakes in the reaction atthe initial stage of the reaction and/or during crystallization.

The feeding composition of each component in the second embodiment ofthe present invention is essentially the same as that in the firstembodiment described above.

However, in this embodiment, it is not necessary that the alkaline earthmetal-containing compound is present during the reaction of the silicasource with the aluminum source. Therefore, in this embodiment, as thefeeding composition of the alkaline earth metal-containing compound, thealkaline earth metal (Me) is expressed in the form of an oxide, and thefeeding composition is such that an MeO/Al₂O₃ molar ratio is preferably0 to 0.1, wherein the MeO/Al₂O₃ molar ratio is more preferably 0.005 ormore, especially preferably 0.01 or more, from the viewpoint of aneffect of making the average primary particle size very fine, andwherein the MeO/Al₂O₃ molar ratio is more preferably 0.08 or less, stillmore preferably 0.05 or less, especially preferably 0.03 or less, fromthe viewpoint of cationic exchange properties.

Embodiments where an alkali metal and/or an alkaline earth metal iscontained in a silica source and/or an aluminum source are the same asthose in the first embodiment described above. In addition, theconcentration of solid content during reaction is the same as that ofthe first embodiment described above.

In the second embodiment of the process for preparing fine zeoliteparticles of the present invention, the reaction is carried out bymixing raw materials mainly comprising a silica source and an aluminumsource in an external circulating line connected to a reaction tank. Inthis case, the reaction can be also carried out as described above withother raw material, preferably the alkaline earth metal-containingcompound as mentioned above, being further fed in the form of asubstantially homogeneous mixture, prepared by mixing the other rawmaterial with a silica source and/or an aluminum source, orsimultaneously with a silica source and/or an aluminum source, orseparately after a silica source and an aluminum source are mixed tostart the reaction therebetween. In addition, the reaction can be alsocarried out as described above, with the alkali metal-containingcompound as mentioned above being further fed in the same manner as thatof the alkaline earth metal-containing compound as desired. It ispreferable that a wet-type mixer (for instance, disintegrators,dispersers, and pulverizers, such as homomic line mills, pipelinehomomixers, homogenizers, static mixers, gear pumps, turbine pumps,centrifugal pumps) is arranged part of the way of the circulating line,so that the slurry formed after feeding each raw materials to thecirculating line can be passed through the circulating line.

The silica source and the aluminum source may be fed into thecirculating line at the same position, or different positions, from eachcorresponding raw material tank; alternatively, one of the silica sourceor the aluminum source may be directly supplied to the reaction tank andcirculated in the circulating line, and the other is fed into thecirculating line from the corresponding raw material tank. Whichever thesilica source or the aluminum source may be fed first, or both thesilica source and the aluminum source may be fed simultaneously. Eachraw material tank is connected to a certain position in the circulatingline via a feed line, preferably to a certain position in thecirculating line connecting between an outlet of a reaction tank and aninlet of a mixer, and each raw material fed from each raw material tankis fed into the circulating line via the feed line. Alternatively, whenone of the raw materials is directly supplied to the reaction tank, thisraw material is mixed in the circulating line with the other rawmaterial fed into the circulating line, the raw material from thereaction tank being circulated in the circulating line. It is preferablethat the synthesis of the fine zeolite particles according to thepresent invention can be efficiently carried out by feeding the rawmaterials a certain position in the circulating line connecting betweenthe outlet of the reaction tank and the inlet of the mixer, and mixingthe raw materials. Here, it is preferable that an agitator equipped withagitation impellers is each arranged inside the reaction tank and insideeach raw material tank, in order that the slurry becomes morehomogeneous in the reaction tank and that the feeding of the rawmaterial in the raw material tank is smoothly carried out.

In the second embodiment of the process for preparing fine zeoliteparticles of the present invention, there are concretely the followingprocesses:

First Preparation Process

This process comprises supplying water to a reaction tank; and feedingan aluminum source and a silica source from each raw material tank intoa circulating line via each feed line, with water being circulated inthe circulating line.

It is preferable that an alkali metal-containing compound is previouslyadded to a silica source and/or an aluminum source; that an alkalimetal-containing compound is simultaneously fed into a circulating linetogether with a silica source and/or an aluminum source from each rawmaterial tank; or that an alkali metal-containing compound is directlysupplied to a reaction tank. It is preferable that a part or an entirepart of an alkaline earth metal-containing compound is previously addedto a silica source. An alkaline earth metal-containing compound may bepreviously added to an aluminum source. Alternatively, an alkaline earthmetal-containing compound may be simultaneously fed together with asilica source and/or an aluminum source from each raw material tank intoa circulating line; or an alkaline earth metal-containing compound maybe fed into a circulating line after previously added to a silica sourceand/or an aluminum source by means of line-mixing wherein a feed linefor the silica source and/or the aluminum source is linked with a feedline for the alkaline earth metal-containing compound at a positionimmediately before the circulating line for line-mixing. In addition, analkaline earth metal-containing compound may be directly supplied to areaction tank.

Second Preparation Process

This process comprises supplying an aluminum source to a reaction tank;and simultaneously feeding a silica source and water into a circulatingline via each feed line from each raw material tank, with the aluminumsource being circulated in the circulating line.

It is preferable that an alkali metal-containing compound is previouslyadded to a silica source and/or water; that an alkali metal-containingcompound is simultaneously fed into a circulating line together with asilica source and/or water from each raw material tank; or that analkali metal-containing compound is directly supplied to a reaction tankand previously added to an aluminum source, or an alkalimetal-containing compound is simultaneously supplied to a reaction tanktogether with an aluminum source. It is preferable that a part or anentire part of an alkaline earth metal-containing compound is previouslyadded to a silica source. Alternatively, an alkaline earthmetal-containing compound may be simultaneously fed together with asilica source from each raw material tank into a circulating line; or analkaline earth metal-containing compound may be fed into a circulatingline after the alkaline earth metal-containing compound is previouslyadded to a silica source by means of line-mixing wherein a feed line forthe silica source is linked with a feed line for the alkaline earthmetal-containing compound at a position immediately before thecirculating line for line-mixing. In addition, an alkaline earthmetal-containing compound may be directly supplied to a reaction tankand previously added to an aluminum source, or an alkaline earthmetal-containing compound may be simultaneously supplied to a reactiontank together with an aluminum source. Further, an alkaline earthmetal-containing compound may be fed together with water.

Third Preparation Process

This process comprises supplying a silica source to a reaction tank; andsimultaneously feeding an aluminum source and water into a circulatingline via each feed line from each raw material tank, with the silicasource being circulated in the circulating line.

It is preferable that an alkali metal-containing compound is previouslyadded to an aluminum source and/or water; that an alkalimetal-containing compound is simultaneously fed into a circulating linetogether with an aluminum source and/or water from each raw materialtank; or that an alkali metal-containing compound is directly suppliedto a reaction tank and previously added to a silica source, or an alkalimetal-containing compound is simultaneously supplied to a reaction tanktogether with a silica source. It is preferable that a part or an entirepart of an alkaline earth metal-containing compound is previously addedto a silica source. The alkaline earth metal-containing compound may bedirectly supplied to a reaction tank and previously added to a silicasource, or an alkaline earth metal-containing compound may besimultaneously supplied to a reaction tank together with a silicasource. Alternatively, an alkaline earth metal-containing compound maybe fed after previously added to or simultaneously fed with an aluminumsource from each corresponding raw material tank into a circulatingline; or an alkaline earth metal-containing compound may be fed into acirculating line after previously added to an aluminum source by meansof line-mixing wherein a feed line for the aluminum source is linkedwith a feed line for the alkaline earth metal-containing compound at aposition immediately before the circulating line for line-mixing.Further, an alkaline earth metal-containing compound may be fed togetherwith water.

The first to third preparation processes described above are preferredembodiments especially when the main reaction is carried out in thereaction tank.

The mixing ratio of the silica source to the aluminum source in thecirculating line can be adjusted depending upon the circulation flowrate and the feed flow rate of each raw material. The mixing ratio, asexpressed by an SiO₂/Al₂O₃ molar ratio, is preferably 0.1 or more, morepreferably 0.5 or more, especially preferably 1 or more, from theviewpoint of oil-absorbing ability. Also, the mixing ratio is preferably3 or less, more preferably 2.5 or less, especially preferably 2 or less,from the viewpoint of flowability of the slurry.

When the reaction is carried out by supplying a silica source or analuminum source to a reaction tank and feeding other raw materials intoa circulating line with the silica source or aluminum source beingcirculated in the circulating line as in the second and thirdpreparation processes, there may be some cases where the mixing ratiochanges with the passage of time owing to the increase in the ratio ofproducts during the reaction. In such a case, by adjusting the rawmaterial concentrations and the circulation flow rate and the like sothat the mixing ratio of the raw materials at the time when the othermaterials are started to be fed, as expressed by an SiO₂/Al₂O₃ molarratio, is preferably 0.1 to 3, more preferably 0.5 to 2.5, especiallypreferably 1 to 2, the desired fine zeolite particles can be obtained inaccordance with the process of the present invention. Here, the mixingratio (molar ratio) is calculated by the following equation:${{Mixing}\quad{Ratio}} = \frac{\left( {{Qs} \times {Cs}} \right)}{\left( {{Qa} \times {Ca}} \right)}$wherein Qa stands for a flow rate (kg/min) of an aluminum source; Castands for a molar concentration (mol/kg) of Al₂O₃ contained in thealuminum source; Qs stands for a flow rate (kg/min) of a silica source;and Cs stands for a molar concentration (mol/kg) of SiO₂ contained inthe silica source.

Here, the reaction temperature, the vigorous agitation at the initialstage of the reaction, the reaction time and the process forcrystallizing zeolite are essentially the same as those in the firstembodiment described above. However, in this embodiment, thecrystallization of zeolite is concretely proceeded by aging with orwithout the slurry circulation in the circulating line after thetermination of the reaction. After the termination of aging, thecrystallization is terminated by filtering and washing the slurry, orneutralizing the slurry with an acid in the same manner as that in thefirst embodiment, to give the fine zeolite particles of the presentinvention.

An especially preferable embodiment for the process for preparing finezeolite particles of the present invention is an embodiment in which thefirst embodiment is combined with the second embodiment described above.In other words, such a preferable embodiment comprises feeding analuminum source and a silica source into a circulating line connected toa reaction tank, and reacting the aluminum source with the silica sourcein the presence of the alkaline earth metal-containing compound. Thealkaline earth metal-containing compound, as described above, can bemade present in the reaction system by, for instance, previously addingthe alkaline earth metal-containing compound to the aluminum sourceand/or the silica source, more preferably previously adding the alkalineearth metal-containing compound to the silica source. The alkaline earthmetal, as mentioned above, is preferably Ca and/or Mg. As to the feedingcomposition of the alkaline earth metal-containing compound, thealkaline earth metal (Me) is expressed in the form of an oxide, and thefeeding composition is such that an MeO/Al₂O₃ molar ratio is preferably0.005 to 0.1, wherein the MeO/Al₂O₃ molar ratio is preferably 0.005 ormore, more preferably 0.01 or more, from the viewpoint of an effect ofmaking the average primary particle size very fine, and wherein theMeO/Al₂O₃ molar ratio is preferably 0.1 or less, more preferably 0.08 orless, still more preferably 0.05 or less, especially preferably 0.03 orless, from the viewpoint of cationic exchange properties. In addition,the alkali metal-containing compound can be used in the same manner asabove. The feeding composition thereof may be the same as that describedabove. The phrase “previously add” in this embodiment may be the same asthat in the second embodiment for the process for preparing fine zeoliteparticles of the present invention.

By reacting the aluminum source with the silica source according to thisembodiment, the desired fine zeolite particles of the present inventioncan be efficiently obtained even in a reaction where the concentrationof the solid content is especially high during the reaction. Inaddition, this embodiment is especially preferable from the viewpointsof improvements in the cationic exchange properties and theoil-absorbing ability. This embodiment is especially effective when theconcentration of the solid content is 25% by weight or more during thereaction, and even when the concentration is as high as 30% by weight ormore, the desired fine zeolite particles of the present invention can beefficiently obtained.

It is preferable that the fine zeolite particles of the presentinvention, obtainable by the process for preparing fine zeoliteparticles of the present invention as explained above, have thefollowing general formula in anhydride form:xM₂O∘ySiO₂∘Al₂O₃∘zMeO,wherein M is an alkali metal; Me is an alkaline earth metal; x is anumber of 0.2 to 2; y is a number of 0.5 to 6; and z is a number of0.005 to 0.1. In the above composition, M is more preferably Na and/orK, and especially preferably Na, from the viewpoints of convenience inthe availability of the raw materials and costs. Me is preferably Caand/or Mg. In addition, x is more preferably a number of 0.6 to 1.3, andy is more preferably a number of 0.9 to 5 z is preferably 0.005 or more,from the viewpoint of making the average primar particle size very fine.z is preferably 0.1 or less, more preferably 0.08 or less, especiallypreferably 0.01 to 0.03, from the viewpoints of cationic exchangeproperties, i.e. cationic exchange speed and cationic exchange capacity.In the second embodiment, it is not necessary that the alkaline earthmetal is present during the reaction of the silica source with thealumina source. Therefore, the values of z in the above general formulamay be preferably 0 to 0.1, and those values of z specified in aboverange are more preferable.

In addition, the fine zeolite particles of the present inventionobtainable 1 the process of the present invention have a known crystalform, as exemplified by A-type, X-type, Y-type, P-type zeolites and thelike. The crystal forms are not particularly limited. X-type and A-typezeolites are preferable, from the viewpoint of cationic exchangeproperties, and A-type zeolite is more preferabl These formedcrystalline phases may a single phase or a mixed phase.

The average primary particle size of the fine zeolite particles of thepresent invention is determined as an average value of directionaldiameter formed by tangents (Feret diameter) obtained by scanningelectron microscope (SEM). The average primary particle size ispreferably 1.5 μm or less, more preferably 1.3 μm or less, from theviewpoint of cationic exchange speed. In addition, the average primaryparticle size is preferably 0.2 μm or more, more preferably 0.5 μm ormore, because when the average primary particle size is exceeding smallthe crystallinity is lowered and the average aggregate particle sizebecomes large.

The term “cationic exchange speed” of the fine zeolite particles of thepresent invention refers to an exchange capacity of Ca ions per oneminute owned by the fine zeolite particles. The cationic exchange speedis preferably 150 mg CaCO₃/g or more, more preferably 170 mg CaCO₃/g ormore, from the viewpoint of deterging performance. On the other hand,the term “cationic exchange capacity” refers to an exchange capacity ofCa ions per 10 minutes owned by the fine zeolite particles of thepresent invention. The cationic exchange capacity is preferably 150 mgCaCO₃/g or more, more preferably 180 mg CaCO₃/g or more, especiallypreferably 200 mg CaCO₃/g or more, from the viewpoint of detergingperformance.

The average aggregate particle size of the fine zeolite particles of thepresent invention is determined by laser diffraction-scattering-typeparticle size distribution analyzer or the like. The average aggregateparticle size is preferably 13 μm or less, more preferably 7 μm or less,especially preferably 1 to 5 μm, from the viewpoints of dispersibilityof the fine zeolite particles and deposition property to clothes whenformulated in a detergent.

Further in the present invention, a dispersion parameter is defined as aproduct of the average primary particle size (μm) multiplied by theaverage aggregate particle size (μm). Those having a dispersionparameter of preferably 7 or less, more preferably 0.1 to 5, generallyhave a cationic exchange speed of 150 mg CaCO₃/g or more, so that theyare suitable as the fine zeolite particles of the present invention.

In addition, when the average primary particle size is denoted by X μm,and the average aggregate particle size is denoted by Y μm, those inwhich X and Y satisfy the relationship of 0.6≦X≦1.5, preferably0.7≦X≦1.2, more preferably 0.8≦X≦1.0, and also satisfy the relationshipof 20X/3-2.4≦Y≦15, wherein Y preferably satisfies a number of 12 orless, more preferably a number of 10 or less, and further satisfy therelationship of X≦Y are preferable owing to their generally excellentoil-absorbing ability. When X and Y satisfy the above relationships inthe resulting fine zeolite particles, there are tendencies that theaverage primary particle size is very fine and that its averageaggregate particle size appropriately develops, and consequently thereare simultaneously caused “formation of gaps between particles” and“exposure of the surface of the primary particles,” whereby theimprovement in the oil-absorbing ability is assumed to be exhibited.

The oil-absorbing ability is expressed by an amount of linseed oilabsorbed as described in detail in Examples. The oil-absorbing abilityis preferably 50 mL/100 g or more, more preferably 70 mL/100 g or more,especially preferably 80 to 130 mL/100 g. With the above-specified rangefor the oil-absorbing ability, the fine zeolite particles arepreferable, from the viewpoint of re-dispersibility.

The fine zeolite particles of the present invention have a very fineaverage primary particle size, excellent cationic exchange propertiesand oil-absorbing ability, a very fine average aggregate particle sizeand also excellent dispersibility. Therefore, the fine zeolite particlescan be suitably used for fillers for paper manufacturing, resin fillers,water treatment agents, detergent builders, oxygen-nitrogen separatingagents, soil improving agents for gardening, polishing agents, and thelike, and the fine zeolite particles are especially suitably used fordetergent builders.

Next, the detergent composition in which the fine zeolite particles ofthe present invention are used as detergent builders will be explained.The content of the fine zeolite particles in the detergent compositionis not particularly limited. The content is preferably 1% by weight ormore, more preferably 3% by weight or more, especially preferably 10% byweight or more, from the viewpoint of exhibiting sufficient detergingperformance. In addition, the content is preferably 80% by weight orless, more preferably 70% by weight or less, especially preferably 60%by weight or less, from the viewpoint of preventing turbidity of thewashing liquid and the deposition to clothes.

The above detergent composition can further comprise a surfactant. Thesurfactant is not particular limited. The surfactant includes, forinstance, nonionic surfactants, anionic surfactants, cationicsurfactants, amphoteric surfactants, and the like.

Concrete examples of the nonionic surfactants include, for instance,known nonionic surfactants described in Tokkyocho Koho: “Shuchi KanyoGijutsu (clothes powder detergent), Chapter 3-1,” published by theJapanese Patent Office.

Particularly, polyoxyethylene oxide and/or polypropylene oxide typenonionic surfactants are preferable, and a polyoxyethylene alkyl etherprepared by adding ethylene oxide in an amount of 5 to 15 moles inaverage to a primary or secondary alcohol having 8 to 16 carbon atoms isespecially preferable.

Other nonionic surfactants include polyoxyethylene alkylphenyl ethers,polyoxyethylene alkylamines, sucrose fatty acid esters, fatty acidglycerol monoesters, higher fatty acid alkanolamides, polyoxyethylenehigher fatty acid alkanolamides, amine oxides, alkyl glycosides,alkylglyceryl ethers, N-alkyl gluconamides, and the like.

The anionic surfactants include, for instance, known anionic surfactantsdescribed, for instance, in Tokkyocho Koho: “Shuchi Kanyo Gijutsu(clothes powder detergent), Chapter 3-1,” published by the JapanesePatent Office.

Concretely, one or more kinds of anionic surfactants selected from thegroup consisting of alkylbenzenesulfonates, alkyl sulfates and alkenylsulfates, polyoxyethylene alkyl ether sulfates (average moles ofethylene oxide: 0.5 to 6), alkyl monophosphates and salts of fattyacids, each having a linear or branched, alkyl or alkenyl group having 8to 22 average carbon atoms, are preferable, among whichalkylbenzenesulfonates and alkyl sulfonates are especially preferable.

The counter ions of these anionic surfactants are selected from thegroup consisting of sodium ions, potassium ions, magnesium ions, calciumions, cations formed by protonation of amines such as ethanolamines,quaternary ammonium salts, and mixtures thereof. When the above anionicsurfactant is used, there may be employed, for instance, a processcomprising formulating an anionic surfactant in an acid form, andseparately adding an alkali thereto.

The cationic surfactants include, for instance, known cationicsurfactants described, for instance, in Tokkyocho Koho: “Shuchi KanyoGijutsu (clothes powder detergent), Chapter 3-1,” published by theJapanese Patent Office. Preferable cationic surfactants include, forinstance, quaternary ammonium salts such as benzalkonium type quaternaryammonium salts.

The amphoteric surfactants include, for instance, those known amphotericsurfactants described, for instance, in Tokkyocho Koho: “Shuchi KanyoGijutsu (clothes powder detergent), Chapter 3-1,” published by theJapanese Patent Office. Preferable amphoteric surfactants include, forinstance, alkylbetaine-type amphoteric surfactants and the like.

The above surfactants may be used alone or in admixture of two or morekinds. In addition, the surfactants may be selected from the same kindof a surfactant as in the case where a plural surfactants are selectedfrom anionic surfactants, or the surfactants may be selected fromvarious different kinds of surfactants as in the case where a pluralsurfactants are selected from anionic surfactants and nonionicsurfactants.

The content of the surfactant in the detergent composition of thepresent invention is not particularly limited. The content of thesurfactant is preferably 1% by weight or more, more preferably 5% byweight or more, especially preferably 10% by weight or more, from theviewpoint of detergency. In addition, the content of the surfactant ispreferably 80% by weight or less, more preferably 60% by weight or less,especially preferably 50% by weight or less, from the viewpoint ofrinsability.

In addition, various additives usually formulated in laundry detergentscan be appropriately formulated in the detergent composition comprisingthe fine zeolite particles of the present invention. The contentsthereof can be appropriately adjusted within a range so as not to impairthe desired effects of the detergent composition of the presentinvention.

The above additives may be those generally used for detergents withoutlimitation. The additives include, for instance, inorganic chelatingagents such as commercially available zeolites (those having an averageprimary particle size exceeding 1.5 μm), amorphous aluminosilicates,crystalline silicates, amorphous silicates, sodium tripolyphosphates,and sodium metasilicate; organic chelating agents such asaminopolyacetates and polyacrylates; anti-deposition agents such ascarboxymethyl cellulose; water-soluble organic solvents such aspolyethylene glycols and glycerol; alkalizing agents such as sodiumcarbonate and potassium carbonate; enzymes such as protease, lipase,cellulase, and amylase; bleaching agents such as sodium percarbonate andsodium perborate; bleaching activators; sodium salts such as sodiumsulfate and sodium chloride; antioxidants; clay minerals; fluorescentdyes; blueing agents; perfumes, and the like.

The detergent composition of the present invention can be obtainedaccording to a known process by mixing each of the above components withstirring, and granulating or the like as desired. Since the resultingdetergent composition comprises the fine zeolite particles of thepresent invention, the composition has very excellent detergency. Thedetergency can be evaluated in accordance with Test Example describedbelow.

Determination values in Examples and Comparative examples were measuredby the following methods. Here, “%” means “% by weight.” In each Table,the units for the cationic exchange speed and the cationic exchangecapacity are each simply expressed as “mg/g.” In addition, sodiumaluminate was used as an aqueous solution of sodium aluminate inExamples and Comparative Examples, unless otherwise specified.

(1) Cationic Exchange Speed

The amount 0.04 g, when calculated as anhydride, of a sample wasaccurately weighed, and added to 100 mL of an aqueous calcium chloride(100 ppm calcium concentration, when calculated as CaCO₃) in a 100 mLbeaker, followed by stirring at 20° C. for 1 minute. Thereafter, themixture was filtered using a membrane filter with 0.2 μm pore size. Theamount 10 mL of the filtrate was taken and assayed for Ca content in thefiltrate by an EDTA titration, and the amount of Ca (when calculated asCaCO₃) ion-exchanged by 1 g of the sample for 1 minute was determined asthe cationic exchange speed (mg CaCO₃/g).

(2) Cationic Exchange Capacity

The amount 0.04 g, when calculated as anhydride, of a sample wasaccurately weighed, and added to 100 mL of an aqueous calcium chloride(100 ppm calcium concentration, when calculated as CaCO₃) in a 100 mLbeaker, followed by stirring at 20° C. for 10 minute. Thereafter, themixture was filtered using a membrane filter with 0.2 μm pore size. Theamount 10 mL of the filtrate was taken and assayed for Ca content in thefiltrate by an EDTA titration, and the amount of Ca (when calculated asCaCO₃) ion-exchanged by 1 g of the sample for 10 minutes was determinedas the cationic exchange capacity (mg CaCO₃/g).

(3) Average Primary Particle Size

The average primary particle size (μm; average value for 50 or moreparticles) was measured by a digitizer (commercially available fromGraphtic, “DIGITIZER KW3300”), with the scanning electronphotomicrographs taken by a field-emission high resolution scanningelectron microscope (FE-SEM, commercially available from Hitachi Ltd.,S400).

(4) Average Aggregate Particle Size

The particle distribution was measured after dispersing a sample inion-exchanged water as a dispersion medium by ultrasonication for 1minute, using a laser diffraction/scattering particle size distributionanalyzer (commercially available from HORIBA Ltd., LA-700). The mediandiameter obtained was considered as an average aggregate particle size(μm).

(5) Oil-Absorbing Ability

The oil-absorbing ability (mL/100 g) was obtained as an amount ofabsorbed linseed oil by a method according to JIS K 5101.

(6) Crystal Form

X-ray diffraction patterns were measured using an X-ray diffractometer(commercially available from K.K. Rigaku, Model: RAD-200) under theconditions of CuK α-ray, 40 kV, and 120 mA. The obtained X-raydiffraction patterns were qualitatively evaluated based on the X-raycrystal diffraction patterns presented in JCPDS (Joint Committee onPowder Diffraction Standards).

EXAMPLE 1

To a 2-liter stainless separable flask (inner diameter: 12 cm) was added1297.2 g of 48% NaOH, and 1000 g of aluminum hydroxide (purity: 99%) wasthen added thereto with agitation. Thereafter, the temperature wasraised, and the mixture was heated at 120° C. for 1 hour. Thereafter,the mixture was cooled, to give sodium aluminate (Na₂O: 21.01%, Al₂O₃:28.18%).

Three-hundred and twenty grams of sodium aluminate obtained by the aboveprocedures was placed in another 2-liter stainless separable flask, andthereafter 316.1 g of 48% NaOH was added thereto. This mixture was usedas an aluminum source.

Next, 355.6 g of No. 3 water glass (Na₂O: 9.68%, SiO₂: 29.83%) wasplaced in a still another 2-liter stainless separable flask, and anaqueous calcium chloride, which was previously prepared by mixing 818.2g of ion-exchanged water with 1.96 g of anhydrous calcium chloride, wasadded thereto with agitation. The resulting water glass solution wasused as a silica source containing an alkaline earth metal. Here, No. 3water glass used was one commercially available from Osaka Keiso.

The above aluminum source was heated to 50° C., with agitating at 300rpm with agitation impellers having an impeller diameter of 11 cm. Inaddition, the silica source was similarly heated to 50° C. When both rawmaterials reached 50° C., the silica source was added dropwise to thealuminum source over 5 minutes using a peristaltic pump. After thetermination of the addition, the reaction was carried out with keepingthe temperature at 50° to 60° C. for 10 minutes. Next, the reactionmixture was heated to 80° C., and thereafter aged for 1.5 hours at 80°C. with agitation. The concentration of the solid content during thereaction was 23%. In addition, an Na₂O/H₂O molar ratio was 0.05.

The resulting slurry was filtered and washed with water until the pH ofthe filtrate attained to 11.4. The resulting residue was then dried at100° C. for 13 hours, to give a zeolite powder.

The composition of the resulting zeolite, in an anhydride form, was 1.09Na₂O∘2.05 SiO₂∘Al₂O₃∘0.02 CaO (x=1.09, y=2.05 and z=0.02). In addition,the crystal form was found to be A-type zeolite belonging to ASTM No.38-241 from the results of the X-ray diffraction patterns.

In addition, the resulting fine zeolite particles had an average primaryparticle size of 0.87 μm, a cationic exchange speed of 184 mg CaCO₃/g,and a cationic exchange capacity of 219 mg CaCO₃/g, and showed excellentcationic exchange properties. Further, the fine zeolite particles had anaverage aggregate particle size of 4.2 μm, and an oil-absorbing abilityof 53 mL/100 g.

EXAMPLES 2 to 6

The synthesis and evaluation of zeolite were carried out in the samemanner as in Example 1, an aluminum source and a water glass solutionwith a different amount of Ca added based on the feeding amount shown inTable 1 as a silica source, prepared in the same manner as in Example 1.As a result, fine A-type zeolite particles having an average primaryparticle size of from 0.75 to 1.3 μm as shown in Table 2 were obtained.

COMPARATIVE EXAMPLE 1

The synthesis and evaluation of zeolite were carried out in the samemanner as in Example 1, except that the synthesis was carried out basedon the feeding composition in Table 1 without addition of an alkalineearth metal. As a result, in the case where an alkaline earth metal wasnot added, the average primary particle size was as large as 1.8 μm, andthe cationic exchange speed was as low as 130 mg CaCO₃/g as shown inTable 2.

COMPARATIVE EXAMPLE 2

The amount 3.5 g of zeolite synthesized in Comparative Example 1 wasadded to 1 L of a 333 mg/L aqueous solution of anhydrous calciumchloride, and the resulting mixture was agitated for 10 minutes.Subsequently, the mixture was filtered using a membrane filter with 0.2μm pore size, and thereafter the resulting residue was washed with 1 Lof ion-exchanged water and dried at 100° C. for 13 hours. Although Ca inthe resulting zeolite was ion-exchanged as shown in the composition ofthe product in Table 2, the change in the average primary particle sizedue to the ion exchange was not found. TABLE 1 Feeding Amount (g)Concentration No. 3 Ion- Anhydrous Feeding Composition of Solid Sodium48% Water Exchanged Calcium (Molar Ratio) Content Aluminate NaOH GlassWater Chloride SiO₂/Al₂O₃ Na₂O/Al₂O₃ CaO/Al₂O₃ (%) Example 1 320 316.1355.6 818.2 1.96 2 4 0.02 23 Example 2 320 316.1 355.6 815.7 0.49 2 40.005 23 Example 3 320 316.1 355.6 818.2 0.98 2 4 0.01 23 Example 4 320316.1 355.6 819.8 2.94 2 4 0.03 23 Example 5 320 316.1 355.6 823.1 4.912 4 0.05 23 Example 6 320 316.1 355.6 828.1 7.85 2 4 0.08 23 Comparative320 316.1 355.6 814.8 0 2 4 0 23 Example 1

TABLE 2 Composition Cationic Exchange of Product Properties (mg/g)Average Average (Anhydride) Cationic Cationic Primary AggregateDispersion Oil-Absorbing (Molar Ratio) Exchange Exchange ParticleParticle Parameter Ability Crystal SiO₂ Na₂O Al₂O₃ CaO Speed CapacitySize X (μm) Size Y (μm) (X × Y) 20X/3 − 2.4 (mL/100 g) Form Example 12.05 1.09 1.0 0.02 184 219 0.87 4.2 3.7 3.4 53 A-type Zeolite Example 22.08 1.09 1.0 0.005 152 215 1.3 4.8 6.2 6.3 58 A-type Zeolite Example 32.07 1.10 1.0 0.010 170 220 1.05 4.5 4.7 4.6 59 A-type Zeolite Example 42.05 1.05 1.0 0.030 165 210 0.75 3.4 2.6 2.6 58 A-type Zeolite Example 51.98 1.06 1.0 0.050 160 200 0.8 3.4 2.7 2.9 59 A-type Zeolite Example 62.01 1.02 1.0 0.080 155 185 0.85 3.3 2.8 3.3 58 A-type ZeoliteComparative 2.09 1.07 1.0 0 130 206 1.8 5.1 9.2 9.6 42 A-type Example 1Zeolite Comparative 2.09 1.01 1.0 0.027 114 197 1.8 5.1 9.2 9.6 42A-type Example 2 Zeolite

EXAMPLE 7

The synthesis and evaluation of zeolite were carried out by the samereaction and process as in Example 1, an aluminum source and a silicasource prepared in the same amounts as in Example 1, and the time foradding the silica source changed to 20 minutes (Table 3). As a result,fine A-type zeolite particles excellent in the cationic exchange speedas shown in Table 4 were obtained, even though the average aggregateparticle size was a slightly large.

EXAMPLE 8

The synthesis and evaluation of zeolite were carried out in the samemanner as in Example 7, an alkaline earth metal salt added beinganhydrous magnesium chloride (Table 3). As a result, similar fine A-typezeolite particles to those obtained in Example 7 as shown in Table 4were obtained.

COMPARATIVE EXAMPLE 3

The synthesis and evaluation of zeolite were carried out in the samemanner as in Example 7. However, an alkaline earth metal was not addedduring the synthesis (Table 3). As a result, the average aggregateparticle size was as large as 28.3 μm, and the cationic exchange speedwas as low as 97 mg CaCO₃/g, as shown in Table 4. TABLE 3 Concen-Feeding Amount (g) Feeding Composition tration No. 3 Ion- AnhydrousAnhydrous (Molar Ratio) of Solid Sodium 48% Water Exchanged CalciumMagnesium SiO₂/ Na₂O/ CaO/ MgO/ Content Aluminate NaOH Glass WaterChloride Chloride Al₂O₃ Al₂O₃ Al₂O₃ Al₂O₃ (%) Example 7 320 316.1 355.6818.2 1.96 0 2 4 0.02 0 23 Example 8 320 316.1 355.6 817.2 0 1.68 2 4 00.02 23 Comparative 320 316.1 355.6 814.8 0 0 2 4 0 0 23 Example 3

TABLE 4 Composition Cationic Exchange Average Average of ProductProperties (mg/g) Primary Aggregate (Anhydride) Cationic CationicParticle Particle Dispersion Oil-Absorbing (Molar Ratio) ExchangeExchange Size Size Parameter Ability Crystal SiO₂ Na₂O Al₂O₃ CaO MgOSpeed Capacity X (μm) Y (μm) (X × Y) 20X/3 − 2.4 (mL/100 g) Form Example7 2.11 1.06 1.0 0.021 0 187 218 0.9 6.9 6.2 3.6 76 A-type zeoliteExample 8 2.07 1.10 1.0 0 0.02 172 210 0.95 7.2 6.8 3.9 82 A-typezeolite Comparative 2.05 1.03 1.0 0 0 97 215 2.1 28.3 59.4 11.6 124A-type Example 3 zeolite

EXAMPLE 9

The synthesis and evaluation of zeolite were carried out in the samemanner as in Example 1, except that the feeding composition ofNa₂O/Al₂O₃ (molar ratio) was changed to 3 (Table 5). An Na₂O/H₂O molarratio during the reaction was 0.04. The resulting product was A-typezeolite having a cationic exchange speed as high as that of Example 1,even though the resulting zeolite had an average primary particle sizeof 1.3 μm which was a slightly larger than that of Example 1, as shownin Table 6.

COMPARATIVE EXAMPLE 4

The synthesis and evaluation of zeolite was carried out in the samemanner as in Example 9. However, an alkaline earth metal was not addedduring the synthesis (Table 5). As a result, the resulting zeolite hadan average primary particle size of as large as 2.2 μm, and a cationicexchange speed of as low as 90 mg CaCO₃/g, as shown in Table 6. TABLE 5Feeding Amount (g) Concentration No. 3 Ion- Anhydrous FeedingComposition of Solid Sodium 48% Water Exchanged Calcium (Molar Ratio)Content Aluminate NaOH Glass Water Chloride SiO₂/Al₂O₃ Na₂O/Al₂O₃CaO/Al₂O₃ (%) Example 9 320 168.8 355.6 727.2 1.96 2 3 0.02 23Comparative 320 168.8 355.6 723.9 0 2 3 0 23 Example 4

TABLE 6 Composition Cationic Exchange Average Average of ProductProperties (mg/g) Primary Aggregate Oil- (Anhydride) Cationic CationicParticle Particle Dispersion Absorbing (Molar Ratio) Exchange ExchangeSize Size Parameter 20X/ Ability Crystal SiO₂ Na₂O Al₂O₃ CaO SpeedCapacity X (μm) Y (μm) (X × Y) 3 − 2.4 (mL/100 g) Form Example 9 2.021.15 1.0 0.019 180 215 1.3 3.3 4.3 6.3 59 A-type zeolite Comparative2.05 1.05 1.0 0 90 198 2.2 16.2 35.6 12.3 98 A-type Example 4 zeolite

Each of apparatus for preparing zeolite used in Examples 10 to 15 willbe explained below based on the apparatus schematically shown in FIGS. 1to 4. Fine zeolite particles were synthesized in an apparatus as shownin each figure, wherein the apparatus comprises a reaction tank equippedwith an agitator and an external circulating line having a mixerarranged part of the way. A raw material tank, a feed line, acirculating line and a reaction tank illustrated in each figure can beappropriately temperature-controlled, but the devices for thetemperature control are not illustrated therein.

An apparatus shown in FIG. 1 comprises an 80-L stainless reaction tank 3equipped with an external circulating line 6 having a mixer 5 (linemill; commercially available from Tokushu Kika Kogyo Co. Ltd., Model:LM-S). A liquid can be conveyed to the circulating line 6 with aliquid-conveying pump 9 (commercially available from Dydo Metal Co.Ltd., WP pump, Model: WP2SS042C0) from the reaction tank 3. Rawmaterials can be fed to a position immediately before the inlet of themixer 5 via a feed line 7 and a feed line 8, respectively, from a rawmaterial tank 1 and a raw material tank 2 (both are 80-L stainlesstanks). In addition, raw materials can be independently fed from the rawmaterial tank 1 and the raw material tank 2, respectively, into thecirculating line 6. The reaction tank 3 was equipped with an agitator 4(used at a rotational speed of 100 rpm for actual use) having agitationimpellers with a diameter of 210 mm. Each of the raw material tank 1 andthe raw material tank 2 was also equipped with the same agitator asabove (not illustrated in FIG. 1).

An apparatus shown in FIG. 2 is constructed so that line-mixing of rawmaterials can be carried out in advance at confluence of a feed line 7and a feed line 8 before raw materials are fed from a raw material tank10 and a raw material tank 11 into a circulating line 6 via the feedline 7 and the feed line 8, respectively. Alternatively, only one of theraw material tanks can be also used. A liquid in the circulating line 6can be conveyed with a liquid-conveying pump 9 (commercially availablefrom Dydo Metal Co. Ltd., WP pump, Model: WP3WL140C0) from a reactiontank 12. Each of the raw material tank 10 and the raw material tank 11was a 200-L stainless tank, the reaction tank 12 was a 350-L stainlesstank having an inner diameter of 750 mm, and a mixer 14 was a line mixer(commercially available from Tokushu Kika Kogyo Co. Ltd., Model: 2S6).An agitator (used at a rotational speed of 100 rpm for actual use)having agitation impellers with a diameter of 210 mm was arranged ineach of the raw material tank 10 and the raw material tank 11, and anagitator 13 (used at a rotational speed of 100 rpm for actual use)comprising one each of a pitch paddle and an anchor paddle, each havinga diameter of 500 mm was arranged in the reaction tank 12. Here, theagitators for the raw material tank 10 and the raw material tank 11 arenot illustrated in FIG. 2.

An apparatus shown in FIG. 3 comprises a 200-L stainless reaction tank16 equipped with an external circulating line 19 having a mixer 18. Aliquid can be conveyed to the circulating line 19 with aliquid-conveying pump 21 (commercially available from Dydo Metal Co.Ltd., WP pump, Model: WP2SS040C0) from the reaction tank 16. A rawmaterial can be fed to a position immediately before the inlet of themixer 18 (line mixer; commercially available from Tokushu Kika Kogyo Co.Ltd., Model: 2S6) via a feed line 20 from a raw material tank 15 (200-Lstainless tank). In addition, an agitator 17 (used at a rotational speedof 100 rpm for actual use) having max-blend type agitation impellerswith a diameter of 340 mm was arranged in the reaction tank 16. Anagitator (used at a rotational speed of 100 rpm for actual use) havingagitation impellers with a diameter of 210 mm (not illustrated in FIG.3) was arranged in the raw material tank 15.

An apparatus shown in FIG. 4 comprises a 350-L stainless reaction tank23 equipped with an external circulating line 26 having a mixer 25. Aliquid can be conveyed to the circulating line 26 with aliquid-conveying pump 28 (commercially available from Dydo Metal Co.Ltd., WP pump, Model: WP3WL140C0) from the reaction tank 23. A rawmaterial can be fed to a position immediately before the inlet of themixer 25 (line mixer; commercially available from Tokushu Kika Kogyo Co.Ltd. Model: 2S6) via a feed line 27 from a raw material tank 22 (200-Lstainless tank). In addition, an agitator 24 (used at a rotational speedof 100 rpm for actual use) comprising one each of a pitch paddle and ananchor paddle, each having a diameter of 500 mm, was arranged in thereaction tank 23. An agitator (used at a rotational speed of 100 rpm foractual use) having agitation impellers with a diameter of 210 mm (notillustrated in FIG. 4) was arranged in the raw material tank 22.

According to each of the apparatus shown in FIGS. 1 to 4, a liquidconveyed from a reaction tank to a circulating line is again returned tothe reaction tank. In the apparatus shown in FIG. 3, it is seen from thefigure that a liquid is returned from a side wall of the reaction tankinto the reaction tank, thereby allowing the liquid to be diffused intoa liquid in the reaction tank. On the other hand, in the apparatus shownin FIGS. 1, 2, and 4, a liquid conveyed from the reaction tank isreturned from a top of the reaction tank through the circulating line,thereby allowing the liquid to be diffused into a liquid in the reactiontank.

EXAMPLE 10

The apparatus shown in FIG. 1 was used. No. 3 water glass was placed ina raw material tank 1; and a 48% aqueous sodium hydroxide and sodiumaluminate were placed in a raw material tank 2; and further, a 35%calcium chloride solution and ion-exchanged water were placed in areaction tank 3. The contents in each tank were heated to 50° C. withagitation until they became homogeneous. While the calcium chloridesolution in the reaction tank 3 was conveyed with a liquid-conveyingpump 9 in advance to a circulating line 6 with operating an agitator 4,the reaction was carried out by simultaneously feeding a silica source(water glass) in the raw material tank 1 and an aluminum source (asodium aluminate solution comprising a 48% aqueous sodium hydroxide andsodium aluminate) in the raw material tank 2 into the circulating line 6via a feed line 7 and a feed line 8 over 2.2 minutes. During thereaction, a mixer 5 was operated at a rotational speed of 1800 rpm.After the termination of the reaction, the circulation of the resultingslurry was stopped. Thereafter, the slurry was heated to 80° C., andaged in this state for 1.5 hours. The resulting slurry was filtered andwashed with water until the pH of the filtrate attained to 11.4.Thereafter, the resulting residue was dried, to give zeolite powder. Thefeeding conditions and the reaction conditions are shown in Table 7, andthe composition and the properties of the resulting zeolite are shown inTable 8. An Na₂O/H₂O molar ratio was 0.04.

EXAMPLE 11

The apparatus shown in FIG. 2 was used. No. 3 water glass was placed ina raw material tank 10; a 35% calcium chloride solution andion-exchanged water were placed in a raw material tank 11; and a 48%aqueous sodium hydroxide and sodium aluminate were placed in a reactiontank 12. The contents in each tank were heated to 50° C. with agitationuntil they became homogeneous. While an aluminum source (a sodiumaluminate solution comprising a 48% aqueous sodium hydroxide and sodiumaluminate) in the reaction tank 12 was conveyed with a liquid-conveyingpump 9 in advance to a circulating line 6 with operating an agitator 13,the reaction was carried out by simultaneously feeding a silica source(water glass) in the raw material tank 10 and the calcium chloridesolution in the raw material tank 11 into the circulating line 6 via afeed line 7 and a feed line 8 over 4 minutes. During the reaction, amixer 14 was operated at a rotational speed of 3600 rpm. While theresulting slurry was continued to be circulated in the circulating line6 even after the termination of the reaction, the slurry was heated to80° C., and aged for 1.5 hours with keeping the slurry at 80° C. Theresulting slurry was filtered and washed with water until the pH of thefiltrate attained to 11.4. Thereafter, the resulting residue was dried,to give zeolite powder. The feeding conditions and the reactionconditions are shown in Table 7, and the composition and the propertiesof the resulting zeolite are shown in Table 8. An Na₂O/H₂O molar ratiowas 0.06.

EXAMPLE 12

The apparatus shown in FIG. 2 was used. A 48% aqueous sodium hydroxideand sodium aluminate were placed in a raw material tank 10; a 35%calcium chloride solution and ion-exchanged water were placed in a rawmaterial tank 11; and No. 3 water glass was placed in a reaction tank12. The contents in each tank were heated to 50° C. with agitation untilthey became homogeneous. While a silica source (water glass) in thereaction tank 12 was conveyed with a liquid-conveying pump 9 in advanceto a circulating line 6 with operating an agitator 13, the reaction wascarried out by simultaneously feeding an aluminum source (a sodiumaluminate solution comprising a 48% aqueous sodium hydroxide and sodiumaluminate) in the raw material tank 10 and the calcium chloride solutionin the raw material tank 11 into the circulating line 6 via a feed line7 and a feed line 8, respectively, over 7 minutes. During the reaction,a mixer 14 was operated at a rotational speed of 3600 rpm. While theresulting slurry was continued to be circulated in the circulating line6 even after the termination of the reaction, the slurry was heated to80° C., and aged for 1.5 hours with keeping the slurry at 80° C. Theresulting slurry was filtered and washed with water until the pH of thefiltrate attained to 11.4. Thereafter, the resulting residue was dried,to give zeolite powder. The feeding conditions and the reactionconditions are shown in Table 7, and the composition and the propertiesof the resulting zeolite are shown in Table 8. An Na₂O/H₂O molar ratiowas 0.06.

EXAMPLE 13

The synthesis of zeolite was carried out without using calcium chloridein the same manner as in Example 12. The feeding conditions and thereaction conditions are shown in Table 7, and the composition and theproperties of the resulting zeolite are shown in Table 8.

EXAMPLE 14

The apparatus shown in FIG. 3 was used. No. 3 water glass was placed andagitated in a raw material tank 15. Thereafter, a calcium chloridesolution obtained by mixing in advance a 35% calcium chloride solutionwith ion-exchanged water was added to the raw material tank 15 over 1minute, and thereafter the resulting mixture was heated to 50° C. Next,sodium aluminate and a 48% aqueous sodium hydroxide were placed in areaction tank 16 while operating an agitator 17, and the resultingmixture was heated to 50° C. After heating, while an aluminum source (asodium aluminate solution comprising sodium aluminate and a 48% aqueoussodium hydroxide) was circulated in a circulating line 19 with aliquid-conveying pump 21, the reaction was carried out by feeding asilica source (a water glass solution comprising No. 3 water glass andthe calcium chloride solution) in the raw material tank 15 into thecirculating line 19 via a feed line 20 over 3.5 minutes. During thereaction, a mixer 18 was operated at a rotational speed of 3600 rpm.While the resulting slurry was continued to be circulated in thecirculating line 19 even after the termination of the reaction, theslurry was heated to 80° C., and aged for 2 hours with keeping theslurry at 80° C. The resulting slurry was filtered and washed with wateruntil the pH of the filtrate attained to 11.4. Thereafter, the resultingresidue was dried, to give zeolite powder. The feeding conditions andthe reaction conditions are shown in Table 7, and the composition andthe properties of the resulting zeolite are shown in Table 8. AnNa₂O/H₂O molar ratio was 0.06.

EXAMPLE 15

The apparatus shown in FIG. 4 was used. No. 3 water glass was placed andagitated in a raw material tank 22, and subsequently a 48% aqueoussodium hydroxide was placed in the raw material tank 22. Thereafter, acalcium chloride solution obtained by mixing in advance a 35% calciumchloride solution with ion-exchanged water was added thereto over 1minute, and the resulting mixture was heated to 50° C. Next, sodiumaluminate was placed in a reaction tank 23 while operating an agitator24, and heated to 50° C. After heating, while an aluminum source (sodiumaluminate) was circulated in a circulating line 26 with aliquid-conveying pump 28, the reaction was carried out by feeding asilica source (a water glass solution comprising No. 3 water glass, the48% aqueous sodium hydroxide and the calcium chloride solution) in theraw material tank 22 into the circulating line 26 via a feed line 27over 8 minutes. During the reaction, a mixer 25 was operated at arotational speed of 2400 rpm. While the resulting slurry was continuedto be circulated in the circulating line 26 even after the terminationof the reaction, the slurry was heated to 80° C., and aged for 1 hourwith keeping the slurry at 80° C. The resulting slurry was filtered andwashed with water until the pH of the filtrate attained to 11.4.Thereafter, the resulting residue was dried, to give zeolite powder. Thefeeding conditions and the reaction conditions are shown in Table 7, andthe composition and the properties of the resulting zeolite are shown inTable 8. An Na₂O/H₂O molar ratio was 0.06. TABLE 7 Examples 10 11 12 1314 15 Feeding Amount (kg) Sodium 15 50.3 95 95 50.0 95 Aluminate 48%NaOH 8.0 26.0 28.2 28.2 26.4 28.2 No. 3 16.7 55.6 105.6 105.6 55.6 105.6Water Glass Ion-Exchanged 37.2 55.7 70.5 71.5 55.7 70.5 Water 35%Calcium 0.29 0.88 1.67 0 0.88 1.67 Chloride Solution Feeding Composition(Molar Ratio) SiO₂/Al₂O₃ 2 2 2 2 2 2 Na₂O/Al₂O₃ 3 3 2.5 2.5 3 2.5CaO/Al₂O₃ 0.02 0.02 0.02 0 0.02 0.02 Reaction Conditions Concentrationof 30 30 33 33 30 33 Solid Content (%) Mixing Ratio 1.9 1.4 1.0 0.58 1.50.59 (Molar Ratio)* Circulating Flow 11.4 21.6 36.2 40.4 27 40.2 Rate(kg/min) Reaction Time 2.2 4 7 8.1 3.5 8 (min)*Molar ratio of SiO₂/Al₂O₃ in a circulating line

TABLE 8 Composition Cationic Exchange Average Average of ProductProperties (mg/g) Primary Aggregate Oil- (Anhydride) Cationic CationicParticle Particle Dispersion Absorbing (Molar Ratio) Exchange ExchangeDiameter Diameter Parameter 20X/ Ability Crystal SiO₂ Na₂O Al₂O₃ CaOSpeed Capacity X (μm) Y (μm) (X × Y) 3 − 2.4 (mL/100 g) Form Example 102.04 1.06 1.00 0.021 191 220 1.3 11 14.3 6.3 82 A-type zeolite Example11 2.04 1.06 1.00 0.017 194 216 1.3 3.3 4.3 6.3 58 A-type zeoliteExample 12 2.04 1.05 1.00 0.017 186 216 0.8 4.1 3.3 2.9 85 A-typezeolite Example 13 2.04 1.07 1.00 0 177 216 1.5 7.6 11.4 7.6 85 A-typezeolite Example 14 2.03 1.09 1.00 0.02 205 220 0.79 5.9 4.7 2.9 70A-type zeolite Example 15 2.05 1.07 1.00 0.02 199 223 0.74 7.2 5.3 2.587 A-type zeolite

In comparison to Comparative Examples 1 to 4, it is seen from Examples 1to 15 that, according to the process for preparing the fine zeoliteparticles of the present invention, A-type zeolite having a very fineaverage primary particle size, being excellent in the oil-absorbingability and the cationic exchange properties, and having a very fineaverage aggregate particle size can be obtained. In addition, it is seenfrom the comparison of Examples 1 to 9 with Examples 10 to 12 andExamples 14 and 15, that a combination of the first embodiment and thesecond embodiment of the process for preparing the fine zeoliteparticles of the present invention is preferable, from the viewpoint offurther improvements in the cationic exchange properties and theoil-absorbing ability. Further, it is seen from the comparison withExamples 14 and 15 that it is particularly preferable to add in advancean alkaline earth metal-containing compound to a silica source from theviewpoint of making the average primary particle size very fine.

TEST EXAMPLE

Each of fine zeolite particles obtained in Example 1 and Example 15 wascompared with zeolite obtained in Comparative Example 1 by the methoddescribed below for the effect on the detergency of the detergentcomposition when the fine zeolite particles were used for the detergentcomposition.

Preparation of Artificially Soiled Cloth

An artificial soil solution having the following composition was smearedto a cloth to prepare an artificially soiled cloth. The smearing of theartificial soil solution to a cloth was carried out by printing theartificial soil solution on a cloth using a gravure roll coater made inaccordance with Japanese Patent Laid-Open No. Hei 7-270395. The processfor smearing the artificial soil solution to a cloth to prepare anartificially soiled cloth was carried out under the conditions of a cellcapacity of a gravure roll of 58 cm³/cm², a coating speed of 1.0 m/min,a drying temperature of 100° C., and a drying time of one minute. As tothe cloth, #2003 calico (commercially available from Tanigashira Shoten)was used.

(Composition of Artificial Soil Solution)

The composition of the artificial soil solution was as follows: Lauricacid: 0.44%, myristic acid: 3.09%, pentadecanoic acid: 2.31%, palmiticacid: 6.18%, heptadecanoic acid: 0.44%, stearic acid: 1.57%, oleic acid:7.75%, triolein: 13.06%, n-hexadecyl palnitate: 2.18%, squalene: 6.53%,liquid crystalline product of lecithin, from egg (commercially availablefrom Wako Pure Chemical Industries): 1.94%, Kanuma red clay forgardening: 8.11%, carbon black (commercially available from Asahi CarbonCo.): 0.01%, and tap water: balance.

Washing Conditions and Evaluation Method

(Composition of Detergent Composition)

Each of the composition of the detergent composition was as follows.Fine zeolite particles of Example 1 or 15, or Comparative Example 1:25%, LAS-Na [one prepared by mixing LAS precursor (NEOPELEX FS,commercially available from Kao Corporation) with a 48% aqueous sodiumhydroxide as a neutralizing agent]: 15%, polyoxyethylene alkyl ether[EMULGEN 108 KM; average mole of ethylene oxide (EO)=8.5, commerciallyavailable from Kao Corporation]: 8%, sodium carbonate (DENSE ASH,commercially available from Central Glass Co., Ltd.): 15%, sodiumsulfate (neutral anhydrous sodium sulfate, commercially available fromShikoku Kasei K.K.): 17%, sodium sulfite (sodium sulfite, commerciallyavailable from Mitsui Toatsu K.K.): 1%, sodium polyacrylate(weight-average molecular weight: 10000, commercially available from KaoCorporation): 4%, and a crystalline silicate (SKS-6, commerciallyavailable from Clariant-Tokuyama K.K.): 15%.

The amount 2.2 kg of clothes (underwear and dress shirt in a proportionof 7:3) were prepared. Next, those referred to as “soiled supportclothes” were prepared by sewing 10 pieces of the artificially soiledclothes of 10 cm×10 cm onto 3 pieces of cotton support clothes of 35cm×30 cm. Washing was carried out by evenly placing the clothes and thesoiled support clothes in a washing machine “AISAIGO (registeredtrademark) NA-F70AP” commercially available from Matsushita ElectricIndustrial Co., Ltd., and adding 20 g of the above detergent compositionto the washing machine. The washing conditions are as follows.

Washing course: standard course;

-   -   concentration of detergent composition: 0.067%;    -   water hardness: 4° DH;    -   water temperature: 10° C.; and    -   liquor ratio: 20 L/kg.

The detergency (%) was determined by measuring the reflectances at 550nm of the unsoiled cloth and the soiled cloth before and after washingby an automatic recording calorimeter (commercially available fromShimadzu Corporation), and taking an average value of 10 pieces.${{Detergency}\quad(\%)} = {\frac{\begin{matrix}{{Reflectance}\quad{of}} \\{{Solid}\quad{Cloth}} \\{{After}\quad{Washing}}\end{matrix} - \begin{matrix}\begin{matrix}{{Reflectance}\quad{of}} \\{{Solid}\quad{Cloth}}\end{matrix} \\{{Before}\quad{Washing}}\end{matrix}}{\begin{matrix}{{Reflectance}\quad{of}} \\{{Unsoiled}\quad{Cloth}}\end{matrix} - \begin{matrix}{{Reflectance}\quad{of}} \\{{Solid}\quad{Cloth}} \\{{Before}\quad{Washing}}\end{matrix}} \times 100}$

As a result, the detergency of the detergent composition comprising thefine zeolite particles of Example 1 was 42%, and the detergency of thedetergent composition comprising the fine zeolite particles of Example15 was 48%. On the other hand, the detergency of the detergentcomposition in which the fine zeolite particles of Comparative Example 1were formulated was as low as 29%. Therefore, it is found that thedetergent compositions comprising the fine zeolite particles of Example1 and Example 15 were more excellent in the detergency over that ofComparative Example 1. It is seen from these results that when using thefine zeolite particles obtained according to the process for preparingthe fine zeolite particles of the present invention for a detergentcomposition, the detergency of the composition is markedly increased.

Industrial Applicability

According to the process for preparing fine zeolite particles of thepresent invention, there can be efficiently obtained fine zeoliteparticles comprising a crystalline aluminosilicate, the fine zeoliteparticles having a very fine average primary particle size, beingexcellent in the oil-absorbing ability and cationic exchange properties,having a very fine average aggregate particle size, and being excellentin the dispersibility. In addition, there can be obtained a detergentcomposition comprising the above fine zeolite particles, the detergentcomposition being excellent in the detergency.

Equivalent

Those skilled in the art will recognize, or be able to ascertain usingsimple routine experimentation, many equivalents to the specificembodiments of the invention described in the present specification.Such equivalents are intended to be encompassed in the scope of thepresent invention as recited in the following claims.

1-14. (canceled)
 15. A process for preparing fine zeolite particlescomprising reacting a silica source with an aluminum source in thepresence of an alkaline earth metal-containing compound by feeding forreaction an aluminum source and/or a silica source into a circulatingline connecting between an outlet for a reaction tank and an inlet of amixer.
 16. The process according to claim 15, wherein the aluminumsource is supplied to the reaction tank and circulated into thecirculating line, and wherein the silica source is fed into thecirculating line.
 17. The process according to claims 15 or 16, whereinthe aluminum source and the silica source are mixed in the circulatingline at a mixing ratio of 0.1 to 3, as expressed by an SiO₂/Al₂O₃ molarratio.
 18. The process according to claims 15 or 16, wherein the finezeolite particles have an average primary particle size of 1.5 μm orless.
 19. The process according to claims 15 or 16, wherein the finezeolite particles have the general formula in anhydride form:xM₂O·ySiO₂·Al₂O₃·zMeO, wherein M is an alkali metal; Me is an alkalineearth metal; x is a number of 0.2 to 2; y is a number of 0.5 to 6; and zis a number of 0.005 to 0.1.
 20. The process according to claims 15 or16, wherein the fine zeolite particles have a cationic exchange speed of150 mg CaCO₃/g or more.
 21. Fine zeolite particles obtainable by theprocess according to the process of claims 15 or
 16. 22. A detergentcomposition comprising the fine zeolite particles of claims 15 or 16.